Delivering results for difficult to express proteins

Based on more than 30 years of innovation in microbial biotechnology, get access to a complete range of strain development services using our XS Microbial Expression Technologies®. Our toolbox of strain design options provides the greatest probability of delivering soluble product while overcoming other expression challenges.  


Access a portfolio of powerful expression tools for microbial strain development

No single host type or vector is capable of being the best expression option for all types of recombinant proteins. To address this, our portfolio of powerful expression tools includes three E. coli, three P. pastoris and two B. subtilis systems. We recently introduced our Pichia 2.0 system that uses a new proprietary inducible promoter, a shorter screening process and has produced high, multi-gram per liter titers with short fermentation times.

During an initial discussion, we gather information about your expression goals including physico-chemical properties and experimental history of your target protein. Based on this information, our strain development scientists design an XS® strain feasibility program tailored to meet your future milestones. 


A program designed around hundreds of host-vector options

The program design is based on a rational selection of hundreds of host-vector options for all or selected hosts that will offer the greatest chance of meeting the desired outcome. Strain development begins with the cloning of the selected expression plasmids. After transformation, thousands of clones can be generated and the primary screen performed in four weeks. 

This approach maximizes the chance of success while minimizing the timeline. Scientists conduct a secondary screening stage which takes approximately two weeks, where the top candidates are evaluated in small scale fermenters to select your best production strain. The scale of the fed-batch fermentation runs can be selected from 0.25 L to 20 L to provide the required purified quantities of your protein for further in-house testing. 


From gene to API production in 12 months–tailored solutions that minimize risk, time, cost and complexity.

Cell banking

The safe and reliable preparation of the production strains is of great importance. It ensures the integrity of the product during its development and allows for consistency during commercial production. Establishing a cGMP master cell bank (MCB) and working cell bank (WCB) is considered the first critical step for the quality of microbial biopharmaceutical production. We offer cGMP-compliant master  and working cell banking services to customers who are using Lonza’s process R&D service platforms. Whether it is strain development, individual cell bank characterization or testing and storage  services, our experienced team will be ready to meet your cell banking needs.

Services Include:

  • Dedicated cGMP facility
  • Qualified and validated equipment
  • Testing and control of all raw material
  • Full documentation to control all activities and aid traceability
  • QA management for supervising all quality relevant aspects
  • Qualified for bio-safety level 1 and 2
  • GMP clean room level grade A, and C for open culture handling
  • Shared glass ware area for media preparation GMP grade D
  • ICH Q7, ICH Q5 and ICH Q6

Testing Options:

  • Culture Viability - Growth performance and living cell count
  • Strain Identity - Microscopic imaging, macroscopic inspection, MicroSeq ID analysis, and specific biochemical features and enzymatic activities
  • Genetic Stability - Mitotic marker retention (in vitro cell age during storage), plasmid preparation or rescue for restriction site mapping, target gene sequencing, chromosomal integration site characterization for Pichia pastoris, PCR and Southern Blot techniques to demonstrate the stability of recombinant co-integrates
  • Purity - Testing for adventitious bacteria, fungi and phage infection
  • Use Testing (only for WCBs) - Growth performance, product formation and identity, and stability after expanded fermentation (in vitro cell age during cultivation)
For difficult to express proteins–our microbial strains deliver expression levels of up to 1g/LFast-Track Expression and Production of Next-Generation Therapeutics with Lonza’s XS® Pichia Platform

Download our Pichia presentation

Fast-Track Expression and Production of Next-Generation Therapeutics with Lonza’s XS® Pichia Platform

Technologies and products


Technology is at the core of our microbial offering.  Our XS Technologies® platform includes Escherichia coli, Pichia pastoris and Bacillus subtilis expression systems. Our XS Technologies® are available for use in your own labs under appropriate commercial terms.